Rotatably selectable high voltage switch



Feb. 7, 1967 Filed Sept. 30, 1964 L. SCOTT ROTATABLY SELEGTABLE HIGHVOLTAGE SWITCH 5 Sheets-Sheet 1 L EWIS SCOTT ATTORNEY Feb. 7, 1967 L.sco'rT 3,303,301

ROTATABLY SELECTABLE HIGH VOLTAGE SWITCH Filed Sept.v 30, 1964 5Sheets-Sheet 2 LEWIS SCOTT BY /MM ATTORNEY Feb. 7, 1961 L. SCQTT3,303,301

ROTATABLY sELEcTABLE HIGH VOLTAGE swITcH Filed sept. 3o, 1964 5Sheets-Sheet 3 INVENTOR L EW/S S0077'v ATTORNEY Feb. 7, 1967 L. scoTr3,303,301

' ROTATABLY SELECTABLE HIGH VOLTAGE SWITCH Filed Sept. 50, 1964 5Sheets-Sheet 4 INVENTOR fw/s scarf ATTORNEY Feb. 7, 1967 L. 5amv3,303,301l

ROTATABLY SELECTABLE HIGH VOLTAGE SWITCH Filed Sept. 30, 1964 5Sheets-Sheet 5 m. LIJ [L 0 oo m l LID v MIGROSWITGH g @l INVENTOR Ew/sscarf I U) O 1 BY ,f f'

ATTORNEY United States Patent O 3,303,301 ROTATABLY SELECTABLE HIGHVOLTAGE SWITCH Lewis Scott, Deale, Md., assigner to the United States ofAmerica as represented by the Secretary of the Navy Filed Sept. 30,1964, Ser. No. 400,614 7 Claims. (Cl. 20d-51.1)

The invention described herein may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

AThe present invention relates generally to a switch and moreparticularly to a mechanical safety switch assembly for switching highcurrent from high voltage capacitors.

In the field of high voltage switches it is the practice to provideeither knife type or plug-in type switches which are suitable in certainapplications but which are impractical where selection is desired. Onthe other hand, selectable switches are usually of the rotatableselectable variety which are inadequate for high current-high voltageoperations. Although such devices have served their intended purpose,they are not entirely satisfactory for all applications, particularly inhigh voltage capacitor switching operations where a selectable plug-intype switch is desired which can be manually operated by a singlecontrol. Also, in capacitor switching operations, prior art devices havenot provided means for shorting the capacitors to insure completedischarge so that operating personnel may safely approach the capacitorunit manually. It has been necessary in high voltage applications forpersonnel t to place heavy bus bars between the selected capacitors andiiash unit. Also the capacitors had to be shorted before they could besafely handled. This shorting operation in itself has proven highlydangerous where inexperienced personnel are involved.

The general purpose of this invention is to provide a high voltagecapacitor switch which embraces all the advantages of prior art devicesand which possesses none of the disadvantages described above. To attainthis, the present invention contemplates a unique switch assembly forswitching high current from high voltage capacitors which iscontrollable by a single selector knob on the front panel of the systemhousing. The selector knob is mounted on a main rod to which the malesection of the switch is connected. When the knob is pulled completelyout, it may be manually rotated to select any of several capacitorvalues. After selection has been made the knob is pushed forward and theswitch is thereby engaged. The main rod has a channel about itsperiphery for receiving a plunger rod afiixed to a time delay relay.This plunger rod is inserted into the channel thereby locking the switchwhen system power is turned on and maintains the switch in the lockedposition until a delay period has elapsed after system power has beenturned off. The delay time allows the capacitors to discharge thro-ugh ableeder network. A shorting means actuated by the main rod is providedwhich shorts the capacitors when the selector knob is pulled out therebyinsuring complete discharge of the capacitors. When the knob is pushedin to engage the switch, the shorting means is removed from its shortingposition by the rod before switch contact is made. A groove forreceiving a bullet catch is also provided in the main rod. As an addedfeature, the lid of the system housing is kept locked in its closedposition while the switch is engaged by means of a bracket atxed to andextending from the lid so that the main' rod passes through it. Also,system power cannot be applied until the lid is closed and the plungerrod of the time delay relay has entered its receiving channel in themain rod.

3,393,3@l Patented F eb. 7, 1367 ICC The switching assembly hereindescribed has general use for high voltage control applications and isof special use in the high voltage flash control unit described incopending application Serial No. 339,038 of Gordon Stamm and Lewis Scottfiled January 20, 1964.

An object of this invention is to provide a new and improved highvoltage switch.

Another object is to provide a high voltage switch which .is rotatablyselectable when the switch is open.

A further object is the provision of a high voltage `switch which ismanually controlled by a single knob.

Still another object is the provision of a high voltage capacitor switchhaving safety features for insuring that the capacitors are completelydischarged before personnel can manually enter for servicing.

Yet another object of the present invention is the 'provision of -a highvoltage capacitor switching and housing assembly whereby the switchingassembly insures that the housing cannot be opened `until the capacitorsare completely discharged.

A still further object of the invention is the provision of a highvoltage capacitor switching assembly and housing in which power cannotbe applied until the switch is properly engaged and the housing lid islocked.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings wherein:

FIG. 1 illustrates a side View of a preferred embodiment of theinvention.

FIG. 2 illustrates a side view of an embodiment of the high voltageswitching assembly.

FIG. 3 is a front view of a disc employed in the embodiment of FIG. 1.l

FIG. 4 is a front view of a plate employed in the embodiment of FIG. l.

FIG. 5 is a front view of a spring finger unit used in the embodiment ofFIG. 1.

FIG. 6 is a front view of a disc used in the embodiment of FIG. 2.

FIG. 7 is a front View of a bodiment of FIG. 2.

FIG. 8(a) is a front view of the spring finger unit used in theembodiment of FIG. 2.

FIG. 8 (b) is side view of one of the spring fingers of the springfinger unit illustrated in FIG. 8(a).

FIG. 9 is a simplified schematic diagram of the switching system.

Referring now to the drawings, wherein like reference charactersdesignate like or corresponding parts through'- out the several Views,there is shown in FIG. 1, which illustrates a preferred embodiment, asystem housing 8 containing the high-voltage capacitor switch 16together with the capacitor assembly 23. A circular glass melamine disc6 (shown in FIG. 3) is supported directly from the front panel 7 of theash unit housing 8 by a square Bakelite support 9 `attached to the outeredge of the disc 6. Insulated disc 6 serves as the female section of theswitch and supports binding post receptacles 11 of the type which canreceive conventional banana plugs 12. Five binding post receptacles 11spaced approximately 30 apart are located about disc 6, as shown in FIG.4, and extend therethrough terminating in nuts 13. Mounted directly inthe center of the disc 6 and extending perpendicularly therefrom is acircular Bakelite support rod 14 which acts as a guide for rod Z5supporting male section 15 of switch 16. Rod 14 extends from disc 6 at adiameter approximately equal to the outer diameter of the hollow portion18 of rod 2S and then continues away from disc 6 toward front panel 7 ata smaller diameter plate employed in the emwhich is slightly less thanthe inner diameter of the hollow portion 18 of rod 25 thereby forming `astop for rod 25 when switch 16 is in its fully closed position. Clrcularrod 14 has an aperture through its center for its entire length forreceiving rod 19 which is iirmly attached to and concentric with rod 25.Male section 15 of switch 16 comprises an aluminum plate 1`7 (shown inFIG. 4.) supporting five banana plugs 12 any one of which 1s capable ofbeing received by any one of the binding posts 11. Banana plugs 12 arefastened to plate 17 by nuts 39. Since plate 17 is conductive all plugs12 are connected in common and lead 43, which is. connected to plate 17by lug 44 under one of the nuts 39, serves as the common output of theswitch for conducting capacitor current to the liash assembly 68. Thealuminum plate 17 is attached to the end of circular hollow Bakeliteportion 18 of rod 25 which slides over the rod 14 in tting engagementtherewith. Concentric with the hollow portion 18 of rod 25 is Bakeliterod 19 having a diameter much smaller than that of rod and extendingbeyond the hollow portion 18 through the aperture in the center ofsupport 'rod 14, through the aperture in the center Iof disc 6, throughan aperture in bottom bracket 21, through an aperture in top bracket 22,and through an aperture in the front panel 38 of capacitor housing 23,to disengage all of the spring fingers 24 from their resting positionbefore the switch is fully engaged. Bottom bracket 21, lid bracket 22,and panel 38 all have their apertures axially aligned so that rod 19passes therethrough to disengage the spring fingers 24.

The hollow portion 18 of rod 25 has a yshallow groove 26 about itsperiphery for receiving bullet catch 27 located within the support 9.Near groove 26 is a channel 28 for receiving plunger rod 29 of relay 31.Rod 25 is of approximately uniform diameter, with the exception of thegroove 26 and channel 28, from the hollow end which supports plate 17back toward the front panel 7 to and including a shoulder forming alimit stop 33. From limit stop 33 a solid portion 34 of rod 25 extendsthrough and beyond the front panel 7 so that a knob 37 can be affixedthereon.

Selector knob 37 has a pointer 35 aiixed thereon. The front panel 7 isengraved with five radial marks spaced 30" apart corresponding to theswitch positions and calibrated in accordance Iwith capacitance. The intensity of the flash provided by ash assembly 68 is proportional to thevalue of capacitance selected. The desired capacitance is selectedbyrotating the selector knob 37 so that the dial pointer 35 is in linewith the radial mark on the front panel 7. After selection has beenmade, the knob is pushed fully forward to engage the switch. i

The square Bakelite support 9 which supports disc 6 has a verticalopening extending completely therethrough for allowing rod 29 of relay31 to pass through support 9 to channel'28 of rod 25, thereby lockingthe rod 29 in the position illustrated in FIG, l 'when the relay 31 isenergized. Relay 31 is attached to the front panel 7 above the switch16. It .is a time delay' relay with the delay operation taking placewhen the relay is deenergized. The relay is a delay-before-breaktype-double-poledouble-throw relay. 'An Agastat type NE 22 QT relay,which hasa` diaphragm or bellows operated by pressure, was modified byattaching a plunger rod to the diaphragm.

A heated treated rhodium flashed beryllium copper spring finger unit 36having five extending fingers 24, as shown in FIG. 5', is supported onthe inside of the panel 38 of capacitor housing 23. Also supported onthe capacitor housing panel 38 and insulated therefrom are ve rhodi umashed cap nuts which act as capacitor contacts 41 and which areindividually connected to their respective capacitor by leads 45. Thecap nuts are aligned with a respective one of the spring lingers 24 andare connected to their respective binding post receptacles by means ofleads 46 having lugs 48 which fit between nuts 13 .and

disc 6. Leads 46 are passed through a slot in panel 38 and around bottombracket 21 to the nuts 13. In their unactuated position, that is whenrod 19 has not pushed the spring fingers 24, the five spring fingers 24rest on the rear of the five capacitor contacts 41.

In operation, the selector knob 37 is pulled out :away from the frontpanel 7 as far as possible, rotated and aligned with the desired radialmark on front panel 7. When the knob is pushed into its full forwardposition the knob 37 is the same distance from the panel as any otherconventional knob control. As the selector 37 is pushed forward, rod 19travels through bottom bracket 21 and lid bracket 22 and then throughthe capacitor housing front panel 38 to push the spring fingers 24 awayfrom the capacitor contacts 41. The portion of rod 19 extending beyonddisc 6 is of such a length that the spring lingers 24 will be pushedaway from their respective contacts 41 before the banana plugs 12 entertheir respective binding post receptacles 11. As the selector knob 37 isstill driven forward the plugs 12 enter and make contact with thecorresponding binding post receptacles 11. With the selector knob 37driven completely forward the bullet catch 27 enters groove 26 and theswitch is ready for flash unit operation. l

With the switch in position, relay 31 will be energized when' power ,isturned on, provided that the lid 44 is on the housing 8. -If lid 44 isnot on housing 8 a lid microswitch (shown schematically in lFIG. 9) willbe open. Since this 'rnicroswitch is serially connected in the powercircuit, relay 31 cannot be energized with the lid off.

When power is turned off, the time delay relay 31 is deenergized and thepreset delay starts. During this delay the switch cannot be opened sincerod 29 locks the switch in position until the end of the delay timewhich is set for a period of time suthcient to allow the high-voltagecapacitors to adequately discharge. The discharge time constant isdetermined by the value of capacitance and also the value of bleederresistance connected to the high-voltage capacitors. At the end of thisdelay, the switch may be pulled open and the spring fingers 24 return totheir resting position on capacitor contacts 41 thereby shorting thecapacitors and insuring complete discharge. v

The switchmust be inthe fully closed position (as illustrated in FIG. l)before power may be applied. vIf partially closed, -rod 29 will preventits associated relay contact (shown schematically in FIG. 9) fromclosing even if the relay coil is energized, thus any possibility ofpower 'being applied to the system before the capacitors are in thecircuit is eliminated. Rod 19 also prevents the lid 44 of system housing`8 from being opened while the switch is engaged, since the rod passesthrough an aperture in lid bracket 22. Bottom bracket 21 and panel 38cooperate to support rod 19 when an attempt is made to remove the lid 44of housing 8.

For purposes of illustration only a single binding post receptacle 111,banana plug 112, capacitor terminal 41', spring finger 24, lead 46, lead45 and capacitor has been shown in FIGS. 1 and 2. However, it isunderstood that five of each of the above components are employed in theembodiments described and illustrated. It is also understood that anyreasonable and workable number of such components may be used within thescope of this invention.

FIG. 5 illustrates the spring linger unit 36 employed in the embodimentof FIG. 1 Ihaving `five spring fingers 24. In the preferred embodimentof FIG. l the end 81 of unit 36 opposite the fingers is fastened by anysuitable means such as a nut and bolt to panel 38 which is maintained atground potential. Openings 82 in spring nger unit 36 shown in FIG. 5provide adequate flexibility when the rod 19 strikes point 83- of the`spring finger unit 36. In PIG. 3 the disc 6 used in the embodiment ofFIG.v 1 is illustrated showing locations 62 of the five binding postreceptacles 11 (shown in FIG. 1) and aperture 63 for receiving rod 19(also shown in FIG. 1). FIG. 4 illustrates aluminum .plate 17 used inthe embodiment of FIG. 1 in which the banana plug positions 72 are showntogether with aperture 73 which passes over rod 14 of FIG. 1.

In FIG. 2 a second embodiment of the invention is illustrated in whichthe finger stock 36 of FIG. 8 is mounted on the rear of glass melaminedisc 6 of FIG. 6. Nuts 13 are replaced by the rhodium flashed cap nuts41 upon which the spring fingers 24 rest and to which the leads from thecapacitor are now directly connected. Disc 6 has apertures for allowingeach push rod actuator 51 affixed to aluminum plate 17 (shown in FIG. 7)to remove one of the spring fingers 24 from its resting position on thecap nut 41. There are five push rod actuators, one for each springfinger 24, which actuators are of such length that the spring fingersact-uated will be separated from their respective contacts a distancesuficient to prevent an electric arc. The spring finger unit 36 employedin the switch embodiment of FIG. 2 is shown in FIG. 8. FIG. 6illustrates the disc 6 (used in'the switch embodiment of FIG. 2) havingapertures 61 for receiving the push rod actuators 51 and shows thepositions 62 of the binding post receptacles 11- FIG. 7 illustratesaluminum plate 17 and shows locations 71 upon which the push rodactuators 51 are affixed as well as locations 72 upon which the bananaplugs 12 are positioned. The aluminum plate 17 of FIG. 7 is used in theswitch embodiment of FIG. 2. Also used in the switch embodiment of FIG.2 is the spring finger unit `36 illustrated in FIG. 8(a) having springfingers 24. The side view of one of the spring fingers 24 illustrated inFIIG. 8(b) shows bend 81 for providing flexibility when the push rodactuators 51 strike point 84 to disengage the spring fingers 24 fromtheir respective capacitor contacts 41.

F'IG. 9 is a simplified schematic diagram of the switching system andshows a portion of disc 6 serving as the female section of switch 16having receptacles 11 which are connected to capacitor network 23. Themale section of switch 16 comprises plate 17 having banana plugs 12which can be inserted into any of the receptacles 11. Male half 17 iscontrolled by rod 25 which can be rotated by selector knob 37 when theswitch is not engaged. The high voltage from plate 17 is directlyconnected to flash assembly 68 by lead 43. Relay 31 is energized toactuate plunger rod 29 when power on switch 9.1 is closed and when lidmicroswitch 92 is closed thereby insuring that the lid is on. If switch16 is not completely engaged so that rod 29` cannot enter channel 28 ofrod 25 then plunger contact 93 will not close thereby prevent-ingapplication of .power to the system, including the high voltagecapacitor section 23 and fiash assembly 68.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood, that within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically described.

What is claimed and des-ired to be secured by Letters Patent of theUnited States is:

1. A switch comprising:

a male section having a plate with a plurality of conductive plfugsmounted thereon,

a female section comprising a stationary circular disc lhaving aplurality of conductive receptacles mounted thereon and aligned forreceiving said plugs,

a circular support rod attached to the center of said disc andperpendicular thereto,

a first rod having one end attached to said male section to enable saidmale section to be rotated and reciprocated into electrical contact withsaid female section,

said first rod being hollow at the end to which said plate is attachedso that said circular support rod fits into said hollow end of saidfirst rod to guide said first rod into a plug and receptacle engagedposition, and

means coupled to said disc and said male section for electricallyshorting said conductive receptacles when said plugs and receptacles aredisengaged.

2. A switch as set forth in claim 1, wherein said means for electricallyshorting comprises a plurality of fiexible conductive fingers each forelectrically shorting a respective one of said receptacles, and furtherincluding:

a first electrical terminal coupled to each of said receptacles on saiddisc,

a second electrical terminal coupled to said plugs, and

means controlled by said first rod for activating or deactivating saidmeans' for shorting.

3. A switch as set forth in claim 2 wherein said means for activating ordeactivating said shorting means comprises a second rod of a diameterwhich is a fraction of the diameter of said first rod concentricallyaligned with and attached to said irst rod, said second rod extendingbeyond said first rod and thro-ugh an aperture in said disc to activatesaid shorting means as a unit, whereby all of the fingers of saidshorting means are displaced from their shorting position before theswitch is closed and as said first rod is pushed forward to engage saidswitch, and whereby said shorting means is allowed to return to itsshorting position across said `receptacles after said switch is opened.

4. A switch as set forth in claim 2 wherein said means for activating ordeactivating said shorting means comprises a plurality of actuator rodsperpendicularly attached to said plate and radially aligned with saidplugs for actuating each of said fingers independently through aperturesin the disc.

5. A switching unit comprising:

a housing having a bottom panel, a front panel having an openingtherein, a rear panel, two side panels, and a lid having a downwardlyextending bracket with aperture therein,

a time delay relay having a .plunger rod attached thereto mounted onsaid front panel,

means for energizing said time delay relay,

a switch assembly including a plug-in type rotatably selectable switchhaving a stationary female end and a male end which is rotatable whensaid switch is open and also movable for engagement with said femaleend,

means for controlling said male end of saidyswitch eX- tending beyondsaid front panel of said housing, supporting means for coupling saidswitch to said front panel,

means in said switch assembly for receiving said plunger rod when saidrelay is energized, whereby said switch is locked into a closedposition, and

means extending from said male end of said switch and passing throughthe aperture in said lid bracket thereby locking said lid onto said unitwhile said lswitch is closed.

6. A switching unit as set forth in claim 5 wherein said male end has aplurality of plugs and said female end has a respective receptacle foreach of said pl-ugs and wherein said switch assembly further comprisesmeans for electrically shorting the receptacles.

7. A high voltage switching system comprising:

a housing having a bottom panel, a front panel having an openingtherein, two side panels and a lid,

a time delay relay having a plunger rod attached thereto mounted on saidfront panel,

means for energizing said relay,

a switch comprising,

a male section having a conductive plate with a plurality of conductive-plugs mounted thereon, a female section comprising a stationaryinsulated circular disc having conductive receptacles mounted thereonand aligned for receiving said plugs,

a first rod having one end attached to said rnale section to enable saidmale section to -be rotated and positioned into electrical contact withsaid female section, said first vrrod being hollow at the end to whichsaid plate is attached, and said first rod having a channel about itsperiphery for receiving 4the plunger rod of said time delay rrelay whenvsaid relay is energized, so that said first rod is locked in positionWhile said plunger rod is in said channel,

l a circular support rod attached .to the center of said disc andperpendicular thereto, said circular support rod fitting into saidhollow end of said first rod to guide said first rod so that said switchcan be guided into an engaged position,

a first terminal coupled to each of said receptacles on said disc, Y

a second terminal coupled to said plugs,

snorting means, coupled to and behind said disc,

. comprising a plurality of flexible conductive fingers each forelectrically contacting a respective .one of said receptacles,

means controlled by said Ifirst rod for activating or deactivating saidsho'rting means comprising a second rod of a diameter which is afraction of the diameter of said first rod, said second lrod extendingbeyond said first rod and through an supporting means coupled betweensaid front panel and the disc of said switch,

a bracket attached to and extending downwardly from said lid and havingan aperture aligned to receive said second rod so that said second rodpasses therethrough and maintains said lid in a closed position whilesaid switch is engaged.

References Cited by the Examiner UNITED STATES PATENTS 8/1929 Coats200-87 X 2,512,880 6/195'0` Russell 20G-4 X 2,594,181 4/1952 Kliegl etal. 2160-4 X 2,608,624 8/ 1952 Goodrich 20 0l2 RGBERT K. SCHAEFER,rimary Examiner.

D. SMITH, JR., Assistant Examiner.

1. A SWITCH COMPRISING: A MALE SECTION HAVING A PLATE WITH A PLURALITYOF CONDUCTIVE PLUGS MOUNTED THEREON, A FEMALE SECTION COMPRISING ASTATIONARY CIRCULAR DISC HAVING A PLURALITY OF CONDUCTIVE RECEPTACLESMOUNTED THEREON AND ALIGNED FOR RECEIVING SAID PLUGS, A CIRCULAR SUPPORTROD ATTACHED TO THE CENTER OF SAID DISC AND PERPENDICULAR THERETO, AFIRST ROD HAVING ONE END ATTACHED TO SAID MALE SECTION TO ENABLE SAIDMALE SECTION TO BE ROTATED AND RECIPROCATED INTO ELECTRICAL CONTACT WITHSAID FEMALE SECTION, SAID FIRST ROD BEING HOLLOW AT THE END TO WHICHSAID PLATE IS ATTACHED SO THAT SAID CIRCULAR SUPPORT ROD FITS INTO SAIDHOLLOW END OF SAID FIRST ROD TO GUIDE SAID FIRST ROD INTO A PLUG ANDRECEPTACLE ENGAGED POSITION, AND MEANS COUPLED TO SAID DISC AND SAIDMALE SECTION FOR ELECTRICALLY SHORTING SAID CONDUCTIVE RECEPTACLES WHENSAID PLUGS AND RECEPTACLES ARE DISENGAGED.